Problem with injectors

[InNeedOfBoost]

Ok, seeing as this is one of the most temperamental cars I've owned...I'll ask this and see what the answer may be ...

I broke the 90* vacuum tee that goes into the brake booster. I used a straight one since it was all I could find locally. Would that make a difference?

[InNeedOfBoost]

Ok, I've listened to the injectors under multiple conditions and I'm convinced they are working properly. Now, I feel that its a vacuum issue...I drove it to work today with no hood on and on my way home, I cracked the window to listen to it under load.

Things I noticed that might help anyone on here point me in the right direction:

1) When its cold, it idles steady at 800, but misfire is still audible. When it warms up/I've been driving for a few, idle fluctuates between 500-800rpms. My normal idle is around 800.

2) I got on it once, got up to about 5500 rpms and let off while still in gear, misfire goes away while decelerating but comes back as soon as I'm on throttle again.

3) When I'm on throttle, I hear my intake BUT I also hear a high pitched whistle, goes away when I'm off throttle. Only does the whistle under load.

4) CEL has NOT come back on since I tried checking for vacuum leaks with brake clean last night. That was the only time it has come on.

Did the stomp test...came up with code 1222:

Lambda control fault code is produced when Motronic system in Bosch control unit receives signal indicating that air/fuel mixture is either excessively rich or excessively lean for period of time loner then 10 seconds. Majority of the causes that affect drivability of the car can be responsible for DME flashing this error:
air leak
defective Air Flow Meter ( AFM)
bad engine temperature sensor
incorrect fuel pressure
problem with injector(s)
defective evaporation system
empty gas tank
issue with spark plugs
problem with valves
etc.

[roguetoaster]

The only time I have heard a whistle in an M42 is when the TB or intake manifolds are not seated correctly. Did you use a new gasket for the TB?

1222 is most commonly a vac leak. However, the hardware components that tend to fail and make it come on are the CTS, O2 sensor and the AFM (at least its carbon track). I just wonder about the intermittent CEL that has vanished.

The straight connector to the booster ought to be okay, as long as the line to it is not kinked or under excessive strain so as to collapse under vacuum load.

[InNeedOfBoost]

That vacuum line is good, its not kinked or anything. Which one is the CTS?

I reused the TB gasket, its was a metal one and looked ok. The center manifold gasket may be my issue. I'll replace both of them for good measure.

[jntar]

Yesterday evening I installed a set of 280155746 injectors into my vehicle. I ended up with the same problem of a misfire and lots of smoke out of the rear. I checked all of the injectors with a battery and they are firing, I also checked the ohm rating on them and they are all within spec. I couldn't narrow down what my issue was, so I put the stock injectors back in. The problem immediately went away.

At this point, I would suggest you place the stock injectors back in and see how it runs.

[InNeedOfBoost]

Dammit, didn't want to hear that. I'll give it a try in the morning, I already have replacement seals for the OE injectors.

[bmwman91]

There are a couple of variations of the 19# mustang injectors. Some of them are too short and don't seat properly, as you have discovered. You can end up with vacuum leaks that way, with air leaking in around the injectors. You would need to shave the 2 rail mounts down a LOT to get things to seat fully, which is not recommended. I don't recall the PN for the correct ones, but there is a big thread on M42Club about it.

As for other likely places for leaks, I would say that there's a good chance that it is the gasket between the upper & lower intake manifolds. The front steel bracket that connects the lower to upper half can cause the upper half to get cocked and not seat well. Loosen up the fasteners holding the steel brackets (front and rear) and the 2 upper nuts on the long studs. Re-torque the 6 (?) nuts that are down by the runners, then the 2 upper ones, and then tighten down the steel brackets.

If your rubber hoses are old, they might have cracked. Did you replace the intake boot? If so, you are likely missing a plastic plug in the bottom. There are 2 holes...1 for the idle control bypass, and the other one is supposed to be plugged, but new boots don't come with the plug.

[InNeedOfBoost]

I have a silicone boot with the fitting from the OE boot for the ICV in it. Hoses all look good, none are dry rotted. Looks like the previous owner did the mess under the intake clean up and replaced all the hoses.

I'll recheck that gasket and tighten it down like you said. If that doesn't work...old injectors are going back in.

[bmwman91]

To be honest, the Mustang injectors don't do shit. I know that it intuitively makes sense that the 4 smaller pintles would atomize the fuel better, but I never noticed any difference at all with them. Their spray pattern is probably somewhat different, and the intake geometry was probably optimized for the stock single pintle injectors' spray pattern.

The Mustang injectors are also of a somewhat different flow rate, which is no good since it just means that the ECU, which is not tuned for them, has to use the O2 sensor to try to make up for that discrepancy.

Go back to stock if you can (not sure how much metal you ground off of the 2 posts...shim them with washers if you need to). A 100% stock M42 with a performance chip and lightweight flywheel is going to give you the most power that you can get with bolt-ons. Everything else is just fluff that sounds neat but hurts power and fuel economy. I assume that this engine is internally stock?

[InNeedOfBoost]

Yes, its stock internally. Next on my list is the TMS chip then the M20 clutch and flywheel setup.

I fixed the problem, I re-installed the old injectors with new seals and got it all back together. No more misfire...

I knew they wouldn't make much of a difference, just better flow from what I heard...which is why I haven't installed them until now (since I was going to have the upper manifold off to clean it up and paint it).

[bmwman91]

Glad to hear that it worked out. Basically, putting different injectors in without a chip tuned for them is a guaranteed recipe for problems. BMW knew what they were doing when they chose the stock injectors. Metric Mechanic told me that the stock ones are good for about 195bhp.